There are three disctinct groups of items a character could craft, each group having its own requirements.

Mundane Items

Basic equipment, simple weapons and armor, etc. Any item that is not related to the Numenera can essentially be made by any character, though depending on the item in question, resources and time are required to craft the item. Creating an item will be a difficult task however, though skills, tools and high quality resources can be used to lower the difficulty of the task. Depending on the item, specific skills might be even be required, for example chemistry in order to create an acid, or forging to make a decent sword.

Cyphers

1. Re-creating the effects of a known Cypher

Re-creating a Cypher has two requirements. Firstly, a character needs to be at least trained in the Numenera skill to even attempt crafting a cypher and secondly the character needs knowledge of the item he is trying to create or modify. Obtaining knowledge of a Cypher can be done in various ways; it can be taught by another character or an NPC; one can attempt to figure out how a Cypher works by dismantling it; or one could simply discover this knowledge over the course of the campaign. Either way, actually learning and retaining this knowledge costs 3 XP. This knowledge can also be kept in various ways in the shape of blueprints, a datapad or something similar. During crafting, other, related skills (such as engineering, chemistry, quantum physics, etc.) or proper tools can be used lower the difficulty. The Numenera skill does not decrease the difficulty however.

2. Creating a new Cypher

Creating an entirely new Cypher also requires being trained in the numenera skill, though does not require the existing knowledge. It is however significantly more difficult than re-creating a known Cypher or Cypher effect. Quickly cobbling together a new Cypher only requires resources and a difficulty test, though this might not guarantee the wanted result. Assembling a Cypher carefully costs 3 XP, though this also grants knowledge of said Cypher, making it easier to create again in the future.

3. Modifying an Existing Cypher

Characters with knowledge of the Numenera and other skills could potentially modify the effects of a cypher. Someone with the demolitionist skill could potentially alter a normal explosive device in to a mine or a shrapnel bomb.

Artifacts

Artifacts are treated on a case-by-case basis, though mastery in the Numenera skill is required. Characters who wish to create a unique, personalized item will need to pay 3 XP. Again, proper skills and tools can be used to reduce the difficulty. Re-creating a lost or destroyed artifact, or repairing a broken one could have a lowered XP cost, or no XP cost at all, depending on the item.